The present invention relates to methods of sanitizing structures, buildings, passenger occupiable vehicles, and other enclosed or enclosable spaces. More particularly, the present invention relates to a method for killing and/or removing pests and their allergens, bacteria, viruses, fungi, molds, volatile organic compounds and other dangerous substances.
It is a common problem that pests, such as insects, rodents and birds, find their way into homes, hotels and other structures. For example, mice, rats, other rodents and birds often find access into a home or building through open doors, crevices, etc., and nest and breed within the house, particularly within the winter months.
The presence of such rodents, or nesting birds or bats, can also introduce other pests and microbes into the structure. For example, fleas, lice and beg bugs often find there way into homes, hotels, etc., by transmission of birds and rodents which nest within the eaves or within the structure of the home or hotel. There are at least 70 different kinds of bed bugs across the world. The blood-sucking parasites are wingless, dark reddish-brown, oval and flat insects. Full-size adults are typically less than one quarter inch long, and mature in about four weeks after hatching, if a host is available. Bed bugs can endure freezing temperatures and use a variety of hosts besides humans, including poultry, rodents, dogs, cats, birds and bats. Although humans rarely feel the approximately 15 minute long bite, some people show sensitive reactions to it. An indication of bed bugs is small blood spots on bed sheets. Bed bugs hide in cracks and crevices during the day, and come out at night to feed. They are found around mattresses, behind picture frames, in night stands, stuffed furniture, behind loose wallpaper, and other enclosed spaces. They will crawl a substantial distance to obtain a blood meal. This is particularly a problem in the hotel industry, where customers can pay several hundred dollars a night for their room, and awake in the room with bed bug bites and bloodied sheets.
In desert settings, it is not uncommon for scorpions to infest homes, and occasionally sting unsuspecting adults or curious children or animals. The scorpions gain access to the dwelling through holes or crevices in the house and are attracted to the moisture and cooler temperatures.
A large number of methods have been developed for killing insects, such as termites, in buildings. The most widely used method is tenting the building, then filling the building with a toxic gas for a period of time sufficient to kill termites or other selected insects. This method is effective for killing termites and other insects. However, this method generally requires 12 to 72 hours to be effective, requiring building occupants to move out and businesses to be closed for approximately a three day period to insure proper venting of toxic material and/or gas. Tenting the building with heavy tarpaulins requires workers to walk and arrange the tarpaulins on the roof, often damaging the roof system. Food and medications must be placed in sealed containers or removed. Generally the entire building must be treated, even if the infestation is localized.
Techniques of varying effectiveness have been developed using heated air or very cold air to kill termites and other organisms. Typical of these are the methods disclosed by Charles Forbes in U.S. Pat. No. 4,817,329, in which wood destroying insects, e.g., termites, are killed by applying a heated gas, such as heated air, to wooden surfaces or the like until the core of wooden structures is heated to a temperature typically about 120° F. to 135° F. This method has been found to be very effective for killing termites. Another alternative to the toxic gas method is disclosed by James J. Chaudoin, et al. in U.S. Pat. No. 4,958,456, in which insects, e.g., roaches, fleas and beetles, are killed by a treatment of building spaces with boric acid and heat. However, the methods disclosed in the Forbes patent are quite complex in the preparation of the building. An enclosing tent structure must be formed around the building to be decontaminated, as the termites and wood eating insects are typically found in the framing, shingles, and outer panels of the building. Tenting the building with heavy tarpaulins requires workers to walk and arrange the tarpaulins on the roof, often damaging the roof system.
Other organisms, such as bacteria, viruses, fungi, and molds such as, but not limited to, aspergillus oryzae, aspergillus terreus, aspergillus versicolor, cladosporium hergbarum, stachybotrys chartarum, penicillium aurantiogriseum, pencillium chrsogenum, pencillium gladrum and fusarium oxysporum, are a serious health hazard even when dead. Many people are allergic to the dust-like remains and residue, i.e., allergens, of these organisms that can also cause serious health problems. This is a particular problem to persons suffering from asthma, bronchitis, pneumoconious and other respiratory ailments, and is a common contributing factor to sick building syndrome (SBS).
It is also well-known that the heated air causes certain molds, fungi, etc. to sporulate, thus releasing spores into the structure and thus dispersing the harmful biological agents and possibly contaminating the structure to a greater degree than originally presented. The use of positive pressure within the structure, as described in Forbes and Hedman et al., further increase the likelihood that the biological contaminants will be dispersed throughout the structure. Forbes also discloses that the heated air can be vented from open windows and the like. However, when treating a contaminated building having harmful viruses, toxic molds, etc., it is not desirable to release such contagions into the air.
Volatile organic compounds (VOCs) have also been implicated as a possible cause of SBS. VOCs can originate from a variety of sources. Commercial examples include by-products of printing shop operations, office machine repairs, blueprint production, photographic processing and food service operations. In residences, such VOCs can include hobbyist products, cosmetics, perfumes, personal hygiene products, aerosol sprays, tobacco smoke, pet urine and even small emissions from the bodies of the occupants. Off-gassing of VOCs is often a common by-product of various building/construction materials, for example paints, adhesives, plastics, carpeting, etc.
Such VOCs are implicated with SBS for mostly two reasons. First, the health effects from exposure to VOCs are consistent with SBS, ranging from irritant effects such as unpleasant odors and mucous membrane irritation, through general systemic effects such as fatigue, nausea, and difficulty concentrating. In addition, they may be of importance because some of them have been shown to have carcinogenic or adverse reproductive effects. Second, indoor concentrations of VOCs, particularly in new buildings, are often greatly elevated with respect to outdoor VOC concentrations. In fact, indoor VOC concentrations have typically been found to be two to ten times higher than outdoor concentrations, and indoor concentrations as much as 100 times higher than outdoor concentrations have been reported in new buildings.
In the northeastern parts of the United States, it is common for heating oil to be delivered and used in the heating of the home during the winter months. The oil can spill, and the fuel oil fumes and odors can infiltrate the house over time and contribute to SBS.
Passenger occupiable vehicles, such as trains, buses, airplanes, etc. also include building/construction materials which are known to off-gas VOC's. Also, the fuel, oil, and grease fumes and odors can infiltrate the passenger compartments of such vehicles and build-up within the seats, carpets, etc. over time. Due to the great number of people regularly traveling in such vehicles, there is an increased chance of coming into contact with contagious bacterium or viruses that can cause illness. Other organisms, such as fungi, and toxic molds can also be potentially found in such vehicles. As the company owning such vehicles necessarily must keep the vehicles running nearly constantly in order to realize the expected profit, such vehicles are rarely cleaned thoroughly. Even if the surfaces are superficially vacuumed and wiped down, there still remain live and dead organisms such as lice, mites, fungi, toxic molds, bacterium, viruses, VOCs, oxidized odors, and potentially insects which may have infested the vehicle, particularly those where food is prepared or served.
A common problem in the wine industry is cork taint. This is most accurately described as a “moldy” or “musty” smell that masks or dominates the fruit aroma of wine and reduces the overall wine quality. Infected wines are said to be “corked” or “corky”. The causes of cork taint are believed to be two-fold. Molds may be originally present in raw cork bark or in wood used for barrels or other winery equipment or facilities, and can infect cork or wood in storage. Ironically, chemicals which react with the molds are introduced by methods and equipment used for keeping the production environment sterile and safe. One culprit is chlorine bleach used in cork processing and also as a routine disinfectant in wineries. Another is atmospheric off-gassing from plastic equipment. TCA, a common abbreviation for various chloroanisole compounds (such as 2,4,6-trichloroanisole, and 2,3,4,6-tetrachloroanisole), is also thought to be a primary cause of cork taint. Damage to the wine industry annually is estimated to be $10 Billion worldwide. A method is needed to prevent or purge TCA, and other atmospheric pollution and residue bleach, from corks and wooden barrels and structures in the production facilities. Similar problems arising from TCA are known to exist in the food and shipping industries.
When constructing new buildings, such as homes and the like, framed with wooden beams, a growing concern is the moisture content of the wood which can result in toxic-mold. Another problem is that framing lumber that has too high a moisture content may lead to shrinkage, resulting in drywall cracking and other problems in the structure. Such moisture-laden or “green” lumber typically has a moisture content between 19%-28%. In the past, construction of a home or building took six months or more, often allowing the wood to naturally dry out over time and reach a stabilized moisture content corresponding with the geographic region, typically less than 15%. It is known that for every 4% of moisture removed from the wood, a corresponding 1% of shrinkage of the wood occurs. Today, buildings and homes are often constructed in three to four months. This is insufficient time to achieve the dimensional stability and drying of the frames. Kiln dried wood, which is wood that has been previously dried in a kiln for 24-48 hours at temperatures between 170°-240° before being used in construction, is commonly being used to meet the fast construction deadlines. However, the cost of kiln-dried lumber ranges from $0.24-$0.30 per board foot, adding an additional $4,000-$5,000 additional lumber cost for a typical 2,000 square foot structure.
Accordingly, there is a need for a system and method for killing and removing biological organisms and reducing odors and volatile organic compounds in enclosures such as commercial and residential buildings, boats, vehicles and portable containers. Such a method should be non-toxic and performed in a relatively short amount of time. Such a method should also effectively kill and remove a large proportion of the dead organisms and substantially reduce volatile organic compounds. There is also a need for a method which can remove moisture from green lumber so as to speed up the construction process and eliminate mold and shrinkage concerns of framing which has too high of a moisture content. The present invention fulfills these needs and provides other related advantages.